Currently, battery-driven electric vehicle and electric buses are gradually replacing conventional vehicle and buses. Battery cells act as a main energy storage device in an electric vehicle. A battery box, as a device for containing the battery cells, is a key component of the electric vehicle, and has a direct influence on the performance of the battery cells and thus on the performance of the electric vehicle. As lithium-ion\batteries have advantages such as the excellent power output performance and a long service life, they have been widely applied in the electric vehicle.
The battery cells, as a main energy storage device in the electric vehicle, is generally consists of a plurality of batteries connected in series or in parallel. The batteries may be subject to liquid leakage after being used for a period of time due to defects or unreasonable installation and fixation structures of the batteries. The leaked electrolyte is a flammable organic material, and is easy to ignite due to sparks or electrostatic discharges when being exposed to the air. This will reduce the safety of the battery pack and endanger the vehicle.
The conventional practice is to detect the liquid leakage through gas detection. The detection principle is generally as follows: due to the battery box is a relatively hermetic space, some gases are often formed and released when the electrolyte is leaked from the battery pack, and these gases can be detected by a gas detector. If these gases are detected by the detector, it represents that an accident of leakage occurs to the battery pack. However, this detection method has some shortcomings: 1. the gas detector is relatively expensive, and cannot deliver a good detection effect when the concentration of the gases is relatively low; and 2. the gas detector cannot work effectively until the gases in the battery box reach a certain concentration and, at this time, a relatively large amount of the electrolyte has been leaked. Because the flammable electrolyte is exposed to the air, this makes accidents of fires and combustion likely to occur.